U.S. patent application number 13/130224 was filed with the patent office on 2011-09-22 for microcapsules and uses thereof.
Invention is credited to Marlene Jacquemond, Lahoussine Ouali.
Application Number | 20110230390 13/130224 |
Document ID | / |
Family ID | 40578173 |
Filed Date | 2011-09-22 |
United States Patent
Application |
20110230390 |
Kind Code |
A1 |
Ouali; Lahoussine ; et
al. |
September 22, 2011 |
MICROCAPSULES AND USES THEREOF
Abstract
The present invention relates to a process for producing
perfume-containing microcapsules having both an aqueous inner phase
and an oily inner phase, which can be used in home or personal care
products, as well as to the process for producing these
microcapsules and the consumer products containing them.
Inventors: |
Ouali; Lahoussine;
(Vetraz-Monthoux, FR) ; Jacquemond; Marlene;
(Viuz-En-Sallaz, FR) |
Family ID: |
40578173 |
Appl. No.: |
13/130224 |
Filed: |
December 17, 2009 |
PCT Filed: |
December 17, 2009 |
PCT NO: |
PCT/IB09/55811 |
371 Date: |
May 19, 2011 |
Current U.S.
Class: |
512/2 ;
512/4 |
Current CPC
Class: |
A61K 2008/115 20130101;
A61K 2800/5426 20130101; A61K 8/87 20130101; A61Q 13/00 20130101;
A61K 8/84 20130101; A61K 2800/412 20130101; C11D 3/0015 20130101;
B01J 13/16 20130101; A61K 2800/56 20130101; A61K 8/11 20130101;
C11D 3/505 20130101; C11D 17/0039 20130101; A61Q 5/02 20130101;
C11D 3/3726 20130101 |
Class at
Publication: |
512/2 ;
512/4 |
International
Class: |
A61K 8/11 20060101
A61K008/11; A61Q 13/00 20060101 A61Q013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 18, 2008 |
EP |
08172188.8 |
Claims
1. A microcapsule comprising: a) a core consisting of at least one
aqueous phase dispersed in a continuous oily phase wherein i. the
aqueous phase is surrounded by a layer formed of the reaction
product of at least one polyisocyanate with at least one organic
compound comprising a permanent quaternary ammonium group and a
primary amine or hydroxyl group; ii. the continuous oily phase
comprises a perfuming ingredient or composition; and b) a shell
surrounding said core and formed of the reaction product of at
least one polyisocyanate with i. at least one organic compound
comprising a permanent quaternary ammonium group and a primary
amine or hydroxyl group; and ii. a polyamine or a polyol.
2. A microcapsule according to claim 1, wherein the aqueous phase
is surrounded by a layer formed of the reaction product of at least
one polyisocyanate with at least one organic compound comprising a
permanent quaternary ammonium group and a primary amine or hydroxyl
group and with a polyamine or a polyol.
3. A microcapsule according to claim 1, wherein the inner aqueous
phase further comprises a hydrophilic active ingredient, preferably
a perfuming ingredient.
4. A microcapsule according to claim 1, wherein the at least one
aqueous phase further comprises silica or other hydrophilic
inorganic particles.
5. A microcapsule according to claim 1, wherein the organic
compound comprising a permanent quaternary ammonium group and a
primary amine group or hydroxyl group is selected from the group
consisting of 2-hydrazino-n,n,n-trimethyl-2-oxoethanammonium
chloride, lysine, arginine, quaternized triethanolamine,
2-aminoethyl-trimethylammonium chloride hydrochloride and
2-hydroxyethyl-trimethylammonium hydroxide.
6. A microcapsule according to claim 5, wherein the organic
compound comprising a permanent quaternary ammonium group and a
primary amine or hydroxyl group is selected from the group
consisting of 2-hydrazino-n,n,n-trimethyl-2-oxoethanammonium
chloride, quaternized triethanolamine and
2-aminoethyl-trimethylammonium chloride hydrochloride.
7. A microcapsule according to claim 1, wherein the polyamine is
guanidine, guanidine carbonate or another water-soluble guanidine
salt.
8. A microcapsule according to claim 1, wherein the polyol is
glycerol.
9. A microcapsule according to claim 1, which is free of polyvinyl
alcohol.
10. A microcapsule according to claim 1, which has a zeta potential
comprised between 40 and 80 mv.
11. A microcapsule according to claim 1, wherein the perfume
content is comprised between 25 and 60% by weight, relative to the
total weight of the microcapsule.
12. A process for the preparation of a microcapsule which
comprises: a) reacting at least one polyisocyanate with at least
one organic compound comprising a permanent quaternary ammonium
group and a primary amine or hydroxyl group, in water or in an
aqueous solution of a hydrophilic active, so as to form an emulsion
of an aqueous phase in the product obtained by such reaction, the
aqueous phase being formed of water or of the aqueous solution of a
hydrophilic active; b) adding an oily phase comprising a perfume
and optionally a polyamine or a polyol to the emulsion obtained in
a); and c) adding water to the emulsion obtained in b) and
optionally adding a polyamine or a polyol, if such a polyamine or
polyol has not yet been added in b) such as to form a
microcapsule.
13. A perfuming composition which comprises: a) as perfuming
ingredient, a microcapsule as defined in claim 1; b) at least one
ingredient selected from the group consisting of a perfumery
carrier and a perfumery base; and c) optionally at least one
perfumery adjuvant.
14. A consumer article, which comprises: a) as perfuming
ingredient, a microcapsule as defined in claim 1; and b) a consumer
product base.
15. (canceled)
16. A consumer article, which comprises: a) as perfuming
ingredient, a perfuming composition according to claim 13; and b) a
consumer product base.
17. A method for intensifying or prolonging the diffusion effect of
the characteristic fragrance of a perfume on a surface, which
comprises treating the surface with a microcapsule according to
claim 1 containing the perfume under conditions which are
susceptible of allowing the release of the perfuming
ingredient.
18. A method for intensifying or prolonging the diffusion effect of
the characteristic fragrance of a perfume on a surface, which
comprises treating the surface with a perfuming composition
according to claim 13 that includes microcapsules containing the
perfume under conditions which are susceptible of allowing the
release of the perfuming ingredient.
19. A method for intensifying or prolonging the diffusion effect of
the characteristic fragrance of a perfume on a surface, which
comprises treating the surface with a perfumed article according to
claim 14, that includes microcapsules containing the perfume under
conditions which are susceptible of allowing the release of the
perfuming ingredient.
20. A method for intensifying or prolonging the diffusion effect of
the characteristic fragrance of a perfume on a surface, which
comprises treating the surface with a perfumed article according to
claim 16, that includes microcapsules containing the perfume under
conditions which are susceptible of allowing the release of the
perfuming ingredient.
Description
TECHNICAL FIELD
[0001] The present invention relates to a process for producing
perfume-containing microcapsules having both an aqueous inner phase
and an oily inner phase, which can be used in home or personal care
products, as well as to the process for producing these
microcapsules and the consumer products comprising them.
PRIOR ART
[0002] One of the problems faced by the perfumery industry lies in
the relatively rapid loss of the olfactive benefit provided by
odoriferous compounds due to their volatility, particularly that of
"top-notes". This problem is generally tackled using a delivery
system, e.g. capsules containing a perfume, to release the
fragrance in a controlled manner.
[0003] Several capsules comprising a multiple core are known form
the prior art. Nevertheless these capsules are very different from
the ones of the present invention.
[0004] For example, WO 2004/041251 describes multicore capsules
having three shells of which at least one comprises a coacervate
complex. Such capsules have a membrane that is rich in water and
less tightly cross-linked than the polyurea or polyurethane walls
of the capsules of the present invention. As a consequence,
perfumes are not sufficiently well retained by this type of
capsules. Moreover, the described coacervated capsules would not be
sufficiently stable in several types of bases commonly used in the
field of functional perfumery.
[0005] S. Kiyoyama et al., Journal of Chemical Engineering of
Japan, vol. 34 (1) (2001), pp. 36-42 describes cross-linked
microcapsules prepared by in-situ copolymerization of styrene and
divinyl benzene in a water-in-oil-in-water emulsion system.
Capsules having walls formed of this type of monomers cannot bear
any cationic charges and are therefore not as well dispersed in the
perfumery base in which they are used and not as well deposited on
the surface on which they are applied, as the cationic polyurea or
polyurethane capsules of the invention.
[0006] U.S. Pat. No. 4,083,798 describes compositions prepared by
dispersing an aqueous phase into an oil phase to form a first
emulsion. This first emulsion is then dispersed as droplets in a
second aqueous phase, in the presence of a water soluble protein
and a gelling polysaccharide. This type of capsule wall is not as
tightly cross-linked as the polyurea or polyurethane walls of the
invention's capsules and therefore they are much less efficient in
retaining perfumes.
[0007] J. A. Hanson et al., Nature, vol. 455 (2008), pp. 85-87,
describes water-in-oil-in-water emulsions stabilized using a
single-component, synthetic amphiphilic diblock copolypeptide
surfactant.
[0008] WO 02/060573 describes a capsule-in-capsule system
consisting of an external capsule with an external capsule envelope
and internal capsules located therein. Both internal and external
capsules can have very diverse types of walls including polyurea or
polyurethane walls. However, the disclosed capsules are not
cationic.
[0009] To summarize, none of the prior known multicore capsules are
at the same time polyurea or polyurethane based and cationic. Other
prior art documents describe polyurea or polyurethane capsules,
some of them being cationic, but none have the same advantageous
characteristics as the invention's capsules. In particular none of
the prior known cationic polyurea and polyurethane capsules has a
multiple core capable of encapsulating both hydrophilic and
hydrophobic ingredients. The prior art never suggests multicore
cationic polyurea or polyurethane microcapsules or the advantageous
properties of such capsules. In particular, multicore polyurea or
polyurethane microcapsules bearing permanent cationic charges
covalently linked to the capsule wall are not disclosed or
suggested.
[0010] The problem of the present invention is that of providing
cationic multicore microcapsules capable of encapsulating both
hydrophilic and hydrophobic materials. The capsules of the
invention solve this problem. Indeed, they have a tightly
cross-linked polyurea or polyurethane wall which is very efficient
in retaining perfuming ingredients. They further have the advantage
of bearing permanent cationic charges with a high charge density
and therefore of having an improved deposition on the surface on
which they are applied and a better dispersion in consumer product
bases. Moreover, the permanent cationic charges are present on
compounds which are covalently linked to the microcapsule wall and
which therefore remain stable on the capsule wall even in the
presence of anionic compounds in the medium in which they are
used.
SUMMARY OF THE INVENTION
[0011] The present invention relates to cationic polyurea or
polyurethane microcapsules having an aqueous inner phase and an
oily inner phase. The invention also concerns the process for
preparing these capsules, as well as perfuming compositions and
perfumed articles containing them.
DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 represents schematically the structure of the
microcapsules of the invention.
[0013] FIG. 2 shows a confocal laser scanning microscopy (CLSM)
image of the microcapsules of the invention as obtained by
transmittance and fluorescence imaging. The inner oily phase is
represented in light grey, whereas the inner aqueous phase is in
dark grey, surrounded by the light grey area.
[0014] FIG. 3 shows the CLSM image of the capsules of the
invention. A very good dispersion is observed.
[0015] FIG. 4 shows the stability of the perfume retention in the
capsules of the invention, when used in a commercial liquid
detergent base.
[0016] FIG. 5 shows the stability of the perfume retention in the
capsules of the invention when used in a fabric softener base.
DETAILED DESCRIPTION OF THE INVENTION
[0017] One object of the present invention is a microcapsule
comprising: [0018] a) a core consisting of at least one aqueous
phase dispersed in a continuous oily phase, wherein [0019] i. the
aqueous phase is surrounded by a layer formed of the reaction
product of at least one polyisocyanate with at least one organic
compound comprising a permanent quaternary ammonium group and a
primary amine or hydroxyl group; [0020] ii. the continuous oily
phase comprises a perfuming ingredient or composition; and [0021]
b) a shell surrounding said core and formed of the reaction product
of at least one polyisocyanate with [0022] i. at least one organic
compound comprising a permanent quaternary ammonium group and a
primary amine or hydroxyl group; and [0023] ii. a polyamine or a
polyol.
[0024] According to one embodiment of the invention, the aqueous
phase is surrounded by a layer formed of the reaction product of at
least one polyisocyanate with at least one organic compound
comprising a permanent quaternary ammonium group and a primary
amine or hydroxyl group and with a polyamine or a polyol.
[0025] In one embodiment of the invention, the polyisocyanate is
reacted not only with the organic compound comprising a permanent
quaternary ammonium group and a primary amine or hydroxyl group,
but also with a polyamine or a polyol, as defined below. In such
case, the layer is formed of the reaction product of at least one
polyisocyanate with at least one organic compound comprising a
permanent quaternary ammonium group and a primary amine or hydroxyl
group and with a polyamine or a polyol.
[0026] FIG. 1 is a schematic representation of the microcapsules of
the invention when the layer surrounding the inner aqueous phase is
formed of the reaction product of at least one polyisocyanate with
at least one organic compound comprising a permanent quaternary
ammonium group and a primary amine or hydroxyl group.
[0027] In the case where the layer surrounding the aqueous phase is
formed of the reaction product of the polyisocyanate with the
organic compound and with a polyamine or polyol, the general
structure of the microcapsule is the same, but the layer
surrounding the inner aqueous phase is crosslinked in the same way
as the external wall of the capsule.
[0028] The aqueous phase comprises water and optionally other water
miscible solvents, preferably together with a hydrophilic active.
Such hydrophilic active is for example a perfume, a colorant, an
antimicrobial or antifungal agent or any other additive of current
use in perfuming compositions, provided that it is soluble in
water. Preferably such hydrophilic active is a perfume. The
hydrophilic active is preferably characterized by a logP value
below 2. The logP value of a compound can easily be determined, for
example by calculation using the EPI suite v3.10, 2000, U.S.
Environmental Protection Agency.
[0029] For the purpose of the present invention, "perfume" means a
single perfuming ingredient or a mixture of ingredients, in the
form of a perfuming composition. By "perfuming ingredients" it is
understood here compounds which are used as active ingredients in
perfuming preparations or compositions in order to impart a hedonic
effect when applied to a surface. In other words, such compounds,
to be considered as being perfuming ones, must be recognized by a
person skilled in the art of perfumery as being able to impart or
modify in a positive or pleasant way the odor of a composition or
of an article or surface, and not just as having an odor. Moreover,
this definition is also meant to include compounds that do not
necessarily have an odor but are capable of modulating the odor of
a perfuming composition, perfumed article or surface and, as a
result, of modifying the perception by a user of the odor of such a
composition, article or surface.
[0030] Specific examples of such perfuming ingredients can be found
in the current literature, for example in Perfume and Flavour
Chemicals, 1969 (and later editions), by S. Arctander, Montclair
N.J. (USA), as well as in the vast patent and other literature
related to the perfume industry. They are well known to the person
skilled in the art of perfuming consumer products, that is, of
imparting a pleasant odour to a consumer product.
[0031] The aqueous phase can also advantageously comprise
hydrophilic inorganic particles such as silica particles or
titanium oxide, in order to adjust the density of the
microcapsules. By so doing, the density of the microcapsules can be
brought to a value similar to that of the end product into which it
is intended to incorporate them and therefore the capsules are
maintained homogeneously suspended and dispersed in such liquid
products. This is particularly advantageous in perfuming
microcapsules because the specific gravity of the perfuming
ingredients is usually lower than 1 g/ml.
[0032] Any polyisocyanate compound is suitable for reacting with
the organic compound and optionally with the polyamine or polyol,
but a polyisocyanate comprising at least two isocyanate groups or
at least three isocyanate groups is preferred. Low volatility
polyisocyanate molecules are preferred because of their low
toxicity. In particular, the polyisocyanate can advantageously be
selected from the group consisting of a trimer of hexamethylene
diisocyanate, a trimer of isophorone diisocyanate or a Biuret of
hexamethylene diisocyanate, among which a Biuret of hexamethylene
diisocyanate is even more preferred.
[0033] The organic compound which is reacted with the
polyisocyanate (referred to herein as "organic compound") can be a
monomer, an oligomer or a polymer, provided that it comprises at
least one permanent quaternary ammonium group and at least one
primary amine or hydroxyl group. By a permanent quaternary ammonium
group, we mean here a quaternary ammonium group which is always
present, and in particular, which is present independently of the
pH. This definition excludes amine groups which are protonated only
at acidic pH. The organic compound therefore bears a permanent
cationic charge.
[0034] Particular examples of suitable compounds for reacting with
the polyisocyanate are
2-hydrazino-N,N,N-trimethyl-2-oxoethanammonium chloride (Girard
reagent T from Acros Organics), the amino acids lysine and
arginine, quaternized triethanolamine,
2-aminoethyl-trimethylammonium chloride hydrochloride and
2-hydroxyethyl-trimethylammonium hydroxide, among which
2-hydrazino-N,N,N-trimethyl-2-oxoethanammonium chloride,
quaternized triethanolamine and 2-aminoethyl-trimethylammonium
chloride hydrochloride are particularly appreciated. The amino
acids lysine and arginine are also particularly useful because they
are natural compounds.
[0035] The amount of polyisocyanate in the microcapsules of the
invention is typically comprised between 2 and 20% by weight,
relative to the total weight of the microcapsule, whereas the
amount of cationic organic compound is typically of from 0.2 to 5%
by weight, these percentages being relative to the total weight of
the microcapsules.
[0036] The continuous oily phase comprises a hydrophobic active.
Such hydrophobic active is for example a perfume, a colorant, an
antimicrobial or antifungal agent or any additive of current use in
perfuming compositions. Preferably such hydrophobic active is a
perfume. The hydrophobic active is preferably characterized by a
logP value above 2. The perfume is as defined above.
[0037] The perfume may be dissolved in a solvent of current use in
the perfume industry. The solvent is preferably not an alcohol.
Examples of such solvents are diethyl phthalate, isopropyl
myristate, Abalyn.TM. (origin: Eastman), benzyl benzoate, ethyl
citrate, limonene or other terpenes, or isoparaffins. Preferably,
the solvent is very hydrophobic and highly sterically hindered,
like for example Abalyn.TM.. The continuous phase may additionally
contain as optional ingredients any other types of hydrophobic
actives and additives commonly used in the field of perfumery.
[0038] The total amount of active, and preferably of perfume, in
the capsules of the invention is typically comprised between 25 and
60% by weight, preferably between 30 and 60% by weight, more
preferably between 40 and 60% by weight, relative to the total
weight of the microcapsules. This amount includes all actives, and
preferably all the perfume, contained in the core (i.e. in the oily
phase as well as in the aqueous phase).
[0039] The core is encapsulated in a crosslinked polyurea or
polyurethane wall formed by reaction of a polyamine or polyol with
at least one polyisocyanate and with at least one cationic organic
compound as described above. An interfacial polymerisation of the
polyamine or polyol with the cationic emulsifier obtained by
reacting the polyisocyanate with the cationic organic compound, as
well as with the free polyisocyanate molecules which are dissolved
in the oily phase, takes place. Firstly, the reaction occurs
between the polyamine or polyol and the emulsifier, which forms a
layer surrounding the core, thus achieving the cross-linking of the
wall. The polyamine or polyol also reacts with free polyisocyanate
molecules which are present near the border of the oily phase. This
double reaction provides a wall bearing cationic charges on the
external side and being sufficiently broad to retain the oily phase
efficiently.
[0040] A polyurea microcapsule wall is formed when a polyamine is
used. Particularly efficient polyamines are water soluble guanidine
salts and guanidine. By "water soluble guanidine salt" it is meant
a salt soluble in water and resulting from the reaction of
guanidine with an acid. One example of such salts is guanidine
carbonate.
[0041] In the case where a polyol is used as the cross-linker, a
polyurethane microcapsule wall is formed. As polyol, glycerol is
preferred.
[0042] The use of specific proportions of polyisocyanate versus
polyamine or polyol is advantageous. Therefore, preferably, for
each mole of isocyanate group, 1 to 10, preferably 2 to 5 moles of
amine or alcohol groups are present. Accordingly there is added an
excess of the cross-linking agent.
[0043] The specific composition of the polyurea or polyurethane
wall is key in obtaining microcapsules that are at the fine balance
between release and retention so as to achieve satisfactory slow
and constant release of fragrances over time, once the capsules are
placed on textiles, skin or hair, while showing the desired
stability of the perfume retention in the product base (e.g.
counteracts efficiently the extraction of the perfume by the
surfactants of the consumer product). The selection of the
polyamine or polyol and of the polyisocyanate, among the ones
mentioned above, enables the fine tuning of the properties and
stability of the capsules.
[0044] Upon their formation using the process described below, the
capsules are dispersed in a continuous outer aqueous phase. However
the capsules of the invention can also be provided in an isolated
or dried form, in which case there does not remain any outer
aqueous phase.
[0045] The microcapsules of the invention are preferably
characterized by a mean diameter comprised between 5 and 100 .mu.m,
preferably between 5 to 50 .mu.m. In the present context, "mean
diameter" refers to the arithmetic mean. With microcapsules of this
size, optimal deposition and/or adherence of microcapsules to the
targeted surface, e.g. textile, hair or skin, is obtained.
[0046] These capsules are also preferably characterized by a zeta
potential comprised between 40 and 80 mV, preferably between 60 and
80 mV. A suitable apparatus for measuring the zeta potential is
Zetasizer Nano ZS (Malvern Instruments).
[0047] Due to the presence of permanent cationic charges at the
surface of the capsules, the zeta potential does not change with
the pH. Moreover, since the cationic charges are covalently linked,
the cationic compounds are not removed even in the present of
anionic compounds such as anionic surfactants that may be
encountered in several consumer product bases. The zeta potential
therefore remains stable in all types of conditions.
[0048] The microcapsules of the invention can be prepared by a
process comprising the following steps [0049] a) reacting at least
one polyisocyanate with at least one organic compound comprising a
permanent quaternary ammonium group and a primary amine or hydroxyl
group in water or in an aqueous solution of a hydrophilic active,
so as to form an emulsion of an aqueous phase in the product
obtained by such reaction, the aqueous phase being formed of water
or of the aqueous solution of a hydrophilic active; [0050] b)
adding an oily phase comprising a perfume and optionally a
polyamine or a polyol to the emulsion obtained in step a); and
[0051] c) adding water to the emulsion obtained in step b) and
optionally adding a polyamine or a polyol, if such a polyamine or
polyol has not yet been added in step b) such as to form a
microcapsule.
[0052] In step a) the isocyanate groups react with the primary
amine or alcohol groups, but they also react with water molecules
and thereby are transformed to amine groups that can react with
isocyanates. This reaction induces a cross-linking in the oil phase
but its rate remains slower than the rate of reaction between the
isocyanate and the primary amine or alcohol. The reaction can also
be carried out when the organic compound contains more than one
reacting group. The product resulting from the reaction of step a)
has the structure of a tenside bearing permanent cationic charges
and acts as en emulsifier. It is therefore referred to herein as
"the emulsifier".
[0053] An emulsion takes place, with droplets of aqueous phase
dispersed in a continuous phase formed of the emulsifier obtained
by the above-described reaction. When the reaction is carried out
in an aqueous solution of hydrophilic actives, such actives remain
in the aqueous phase of the emulsion.
[0054] The reaction of the polyisocyanate with the cationic organic
compound is typically carried out at a temperature comprised
between 20 and 70.degree. C.
[0055] In step b), the oily phase comprising a hydrophobic active,
as described above, is admixed with the emulsion obtained in step
a). A new emulsion is formed, wherein the aqueous phase formed in
step a) is dispersed in the oily phase. A layer of the emulsifier
formed in step a) is formed at the interface of the aqueous and
oily phases.
[0056] In one embodiment of the invention, a polyamine or a polyol
is added in step b) together with the oily phase, so that the
polyamine of polyol reaches the membrane surrounding the aqueous
phase droplets thereby ensuring optimal cross-linking of this
internal membrane.
[0057] The addition of water in step c) results in the formation of
droplets of oily phase dispersed in water, which forms a continuous
phase. The aqueous phase droplets surrounded by the emulsifier, as
obtained in step b), remain dispersed in the oily phase, so that
such aqueous phase droplets are dispersed in the newly formed oily
phase droplets. A layer of the emulsifier obtained in step a) is
formed at the newly formed interface between water and the
dispersed droplets of oily phase. The emulsifier at the interface
of the oily phase and water is cross-linked by the effect of the
polyamine or polyol, so as to form the outer capsule wall. The
cross-linking of the outer wall is achieved in the same way when
the polyamine or polyol is added in step b) or in step c).
[0058] In a preferred embodiment of the invention, the polyamine or
polyol is not added in step b), but in step c).
[0059] To achieve optimal cross-linking, for each mole of
isocyanate group used in step a), 1 to 10, preferably 2 to 5 moles
of amine or alcohol groups are preferably added in step b) or
c).
[0060] The crosslinking of the polyurea or polyurethane wall is
usually performed at temperatures ranging from 20 to 85.degree. C.
Preferably the reaction is maintained for 2 to 15 hours, more
preferably for 4 to 10 hours. The reaction between the
polyisocyanate and the polyol involves the use of a catalyst such
as 1,4-diazabicyclo[2,2,2]octane.
[0061] In the case of a polyurethane wall, the cross-linking step
can be carried out either in basic, neutral or acidic medium,
whereas the cross-linking of the polyurea wall is carried out at a
pH above 9.
[0062] The definition and the concentration of each component used
in the process of the invention are as described above in the part
of the description related to the capsules themselves.
[0063] The process of the invention may further comprise the step
of forming a powder with microcapsules using methods commonly known
in the art, as for example spray drying.
[0064] The process of the invention has the advantage of being
carried out in the absence of polyvinyl alcohol. Polyvinyl alcohol
is used in many emulsification processes leading to polyurea and
polyurethane microcapsules. Nevertheless, it causes strong phase
separation in some liquid detergent formulations. Therefore, due to
the fact that they are free of polyvinylalcohol, the microcapsules
of the invention do not phase separate when incorporated in liquid
detergent bases.
[0065] The microcapsules of the invention can be advantageously
used for the controlled release of the encapsulated perfume. It is
therefore particularly appreciated to include these microcapsules
as perfuming ingredients in a perfuming composition or in perfumed
consumer products.
[0066] Therefore, another object of the present invention is a
perfuming composition comprising: [0067] a) as perfuming
ingredient, a microcapsule of the invention, as defined above;
[0068] b) at least one ingredient selected from the group
consisting of a perfumery carrier and a perfumery base; and [0069]
c) optionally at least one perfumery adjuvant.
[0070] By "perfumery carrier" we mean here a material which is
practically neutral from a perfumery point of view, i.e. that does
not significantly alter the organoleptic properties of perfuming
ingredients. Said carrier may be a liquid.
[0071] As liquid carrier one may cite, as non-limiting examples, an
emulsifying system, i.e. a solvent and a surfactant system, or a
solvent commonly used in perfumery. A detailed description of the
nature and type of solvents commonly used in perfumery cannot be
exhaustive. However, one can cite as non-limiting example solvents
such as dipropyleneglycol, diethyl phthalate, isopropyl myristate,
benzyl benzoate, 2-(2-ethoxyethoxy)-1-ethanol or ethyl citrate,
which are the most commonly used.
[0072] Generally speaking, by "perfumery base" we mean here a
composition comprising at least one perfuming co-ingredient
together with the capsules of the invention.
[0073] The "perfuming co-ingredients" can be any perfuming
ingredient, as defined above.
[0074] Generally speaking, by "perfumery adjuvant" we mean here an
ingredient capable of imparting an added benefit such as a color, a
particular light resistance, chemical stability, etc. A detailed
description of the nature and type of adjuvants commonly used in
perfuming bases cannot be exhaustive, but such ingredients are well
known to a person skilled in the art.
[0075] A composition consisting of microcapsules as defined above
and at least one perfumery carrier, represents a particular
embodiment of the invention. Another embodiment of the invention is
one such perfuming composition further comprising at least one
perfumery base, and optionally at least one perfumery adjuvant.
[0076] Furthermore, microcapsules as defined above or a perfuming
composition comprising such microcapsules, are useful perfuming
ingredients, which can be advantageously used in all the fields of
modern perfumery, such as fine perfumery or functional perfumery.
Indeed, the microcapsules and the perfumes containing them may be
advantageously employed in fine or functional perfumery to achieve
a more controlled deposition, and consequent release, of perfuming
ingredients.
[0077] The microcapsules of the invention and the perfuming
compositions containing them can be used in various types of
perfumed consumer products. This result is highly surprising since
said consumer products may contain high amounts (typically more
than 10% of their own weight) of specific types of
surfactant/tensioactive/solvents and which are known to
significantly diminish the stability and the performance of said
capsules. In other words, the use of the invention's microcapsules
in the consumer products provides unexpected advantages over the
same use of prior art capsules.
[0078] The microcapsules of the invention provide improved
deposition of the perfume on the treated surface together with an
improved stability in a chemically aggressive environment and thus
a good retention of the perfume, especially in detergents and
fabric softeners. The cationic polyurea microcapsules are also well
dispersed in the consumer product bases, so that no phase
separation is induced upon addition of the capsules to the base and
during a sufficient storage period. The microcapsules of the
invention provide a controlled release of the encapsulated perfume,
said perfume being slowly released from the microcapsules, thus
considerably improving the perfume long-lastingness and
intensity.
[0079] Consequently, a perfumed article comprising: [0080] a) as
perfuming ingredient, a microcapsule as defined above or a
perfuming composition as defined above; and [0081] b) a consumer
product base; is also an object of the present invention.
[0082] For the sake of clarity, it has to be mentioned that, by
"consumer product base" we mean here a consumer product which is
compatible with perfuming ingredients. In other words, the consumer
product base comprises the functional formulation, as well as
optionally additional benefit agents, corresponding to a consumer
product. The microcapsules of the invention are incorporated to the
consumer product base in an olfactively effective amount.
[0083] The nature and type of the constituents of the consumer
product do not warrant a more detailed description here, which in
any case would not be exhaustive, the skilled person being able to
select them on the basis of its general knowledge and according to
the nature and the desired effect of said product.
[0084] Examples of suitable consumer product bases include solid or
liquid detergents and fabric conditioners, heavy duty cleaners, as
well as any other product commonly used in perfumery, namely
perfumes, colognes or after-shave lotions, perfumed soaps, shower
or bath salts, mousses, creams, oils or gels, hygiene products or
hair care products such as shampoos, body-care products, deodorants
or antiperspirants, air fresheners and also cosmetic preparations.
As detergents it is intended to include here applications such as
detergent compositions or cleaning products for washing up,
cleaning or treating various surfaces, e.g. intended for textile,
dish or hard-surface treatment, whether they are intended for
domestic or industrial use. Other perfumed articles are fabric
conditioners, ironing waters, papers, wipes or bleaches.
[0085] Preferred perfumed articles are powder and liquid
detergents, fabric conditioners and hair care products such as
shampoos.
[0086] The proportions in which the microcapsules of the invention
can be incorporated into the various aforementioned articles or
compositions vary within a wide range of values. These values are
dependent on the nature of the article or product into which they
are to be incorporated and on the desired olfactory effect, as well
as the nature of the co-ingredients in a given composition, when
the microcapsules are mixed with perfuming co-ingredients, solvents
or additives commonly used in the art.
[0087] For example, typical concentrations of the capsules of the
invention in a perfuming composition such as described above may
vary within a wide range of values comprised between 1% and 40% by
weight, preferably between 5% and 20% by weight, relative to the
weight of the perfuming composition. Concentrations lower than
these, such as in the order of 0.001% to 5%, more preferably 0.3 to
2%, or even 0.5 to 1%, by weight, relative to the total weight of
the consumer product, can be used when these compounds are applied
directly in the perfuming of the various consumer products
mentioned hereinabove.
[0088] Formulations of consumer product bases in which the
microcapsules of the invention can be incorporated can be found in
the abundant literature relative to such products. These
formulations do not warrant a detailed description here, which
would in any case not be exhaustive. The person skilled in the art
of formulating such consumer products is perfectly able to select
the suitable components on the basis of his general knowledge and
of the available literature. In particular, examples of such
formulations can be found in the patents and patent applications
relative to such products, for example in WO 2008/016684 (pages 10
to 14), in US 2007/0202063 (paragraphs [0044] to [0099]), in WO
2007/062833 (pages 26 to 44), in WO 2007/062733 (pages 22 to 40),
in WO 2005/054422 (pages 4 to 9), in EP 1741775, in GB 2432843, in
GB 2432850, in GB 2432851 or in GB 2432852.
[0089] Another object of the present invention is a method for
intensifying or prolonging the diffusion effect of the
characteristic fragrance of a perfume on a surface, characterized
in that said surface is treated with [0090] a) a microcapsule of
the invention, as defined above, containing said perfume; [0091] b)
a perfuming composition of the invention, as defined above,
comprising the microcapsule of a); or [0092] c) a perfumed article
of the invention, as defined above, comprising the microcapsule of
a); under conditions which are susceptible of allowing the release
of the perfuming ingredient.
[0093] Suitable surfaces for such treatment are in particular
textiles, hard surfaces, hair and skin.
[0094] Is also encompassed by the present invention a method for
prolonging the effect of a perfume intended for application on a
surface, said process comprising: [0095] a) reacting at least one
polyisocyanate with at least one organic compound comprising a
permanent quaternary ammonium group and a primary amine or hydroxyl
group in water or in an aqueous solution of a hydrophilic active,
so as to form an emulsion of an aqueous phase in the product
obtained by such reaction, the aqueous phase being formed of water
or of the aqueous solution of a hydrophilic active; [0096] b)
adding an oily phase comprising a perfume and optionally a
polyamine or a polyol to the emulsion obtained in step a); [0097]
c) adding water to the emulsion obtained in step b) and optionally
adding a polyamine or a polyol, if such a polyamine or polyol has
not yet been added in step b), so as to form a microcapsule; and
[0098] d) applying the microcapsule obtained in step c) to the
surface.
[0099] The capsules of the invention and the process to prepare
them will be further illustrated in the examples below.
EXAMPLES
Example 1
Preparation of Microcapsules According to the Invention
[0100] A perfuming composition intended to be encapsulated was
prepared by admixing the following ingredients, in the amounts
indicated.
TABLE-US-00001 TABLE 1 perfuming composition Ingredients Parts by
weight (%) Hexyl salicylate 20 Romascone .RTM..sup.1) 20 Lilial
.RTM..sup.2) 20 Lorysia .RTM..sup.3) 20 Verdox .RTM..sup.4) 20
.sup.1)Methyl 2,2-dimethyl-6-methylene-1-cyclohexanecarboxylate,
origin: Firmenich SA, Geneva, Switzerland
.sup.2)3-(4-Tert-butylphenyl)-2-methylpropanal, origin: Givaudan
SA, Vernier, Switzerland .sup.3)4-(1,1-Dimethylethyl)-1-cyclohexyl
acetate, origin: Firmenich SA, Geneva, Switzerland
.sup.4)2-tert-butyl-1-cyclohexyl acetate, origin: International
Flavors and Fragrances,USA
[0101] The microcapsules of the invention were then prepared by the
following process.
[0102] a) An amount of 1.55 g of Girard Reagent T
(2-hydrazino-N,N,N-trimethyl-2-oxoethanammonium chloride, origin:
Acros Organics) was dissolved in 1.07 g of water containing traces
of fluorescin. This solution was mixed with 3.33 g of Desmodur.RTM.
N100 (solvent-free aliphatic polyisocyanate resin based on
hexamethylene diisocyanate, origin: Bayer) using an Ultra Turax at
24000 rpm for 2 minutes. The resulting solution was kept at room
temperature under magnetic stirring for 2 hours.
[0103] b) The reaction mixture was then dispersed in 30.0 g of the
perfume described in Table 1 containing traces of Nile Red using an
Ultra Turax at 24000 rpm for 3 minutes.
[0104] c) An aqueous solution of guanidine carbonate was then
prepared by dissolving 2.64 g of guanidine carbonate (origin:
Fluka) in 6.06 g of water. The obtained solution was gradually
added to the reaction mixture obtained in step b). The system was
then maintained at 70.degree. C. for 3 hours under mechanical
stirring of 500 rpm.
[0105] The obtained capsules were then characterized. A mean
particle size of 10 .mu.m was measured by laser diffraction
measurements (MasterSizer, Malvern Instruments Ltd). A zeta
potential of 65.9.+-.0.6 mV was measured with a Zetasizer Nano ZS
(Malvern Instruments Ltd). This high value indicates a high density
of the cationic charges at the surface of the microcapsules.
Example 2
Preparation of Microcapsules According to the Invention
[0106] a) An amount of 1.46 g of Girard Reagent T
(2-hydrazino-N,N,N-trimethyl-2-oxoethanammonium chloride, origin:
Acros Organics) was dissolved in 2.02 g of water containing traces
of fluorescin. This solution was mixed with 6.75 g of Desmodur.RTM.
N100 (solvent-free aliphatic polyisocyanate resin based on
hexamethylene diisocyanate, origin: Bayer) using an Ultra Turax at
24000 rpm for 2 minutes. The resulting solution was kept at room
temperature under magnetic stirring for 2 hours.
[0107] b) The reaction mixture was then dispersed in 30.1 g of the
perfume described in Table 1 containing traces of DABCO
(1,4-diazabicyclo [2.2.2]octane, origin: Fluka) and of Nile Red
using an Ultra Turax at 24000 rpm for 5 minutes.
[0108] c) The system was then stirred continuously with vortex
stirrer at 400 rpm. An aqueous solution of glycerol (origin: Fluka)
was then prepared by dissolving 2.73 g of guanidine carbonate in
5.41 g of water. The obtained solution was then added in two
portions to the reaction mixture obtained in step b). The system
was then maintained at 70.degree. C. for 21 hours under mechanical
stirring of 500 rpm.
[0109] The obtained capsules were then characterized. A mean
particle size of 18 .mu.m was measured by laser diffraction
measurements (MasterSizer, Malvern Instruments Ltd). A zeta
potential of 73.3.+-.5.0 mV was measured with a Zetasizer Nano ZS
(Malvern Instruments). This high value indicates a high density of
the cationic groups at the surface of the microcapsules.
Example 3
Preparation of Microcapsules According to the Invention
[0110] a) An amount of 0.75 g of Girard Reagent T
(2-hydrazino-N,N,N-trimethyl-2-oxoethanammonium chloride, origin:
Acros Organics) was dissolved in 1.07 g of water containing traces
of fluorescin. This solution was mixed with 3.33 g of Desmodur.RTM.
N100 (solvent-free aliphatic polyisocyanate resin based on
hexamethylene diisocyanate, origin: Bayer) using an Ultra Turax at
21500 rpm for 2 minutes. The resulting solution was kept at room
temperature under magnetic stirring for 2 hours.
[0111] b) The reaction mixture was then dispersed in 15.1 g of the
perfume described in Table 1 containing traces of Nile Red using an
Ultra Turax at 21500 rpm for 2 minutes.
[0112] c) An aqueous solution of guanidine carbonate was then
prepared by dissolving 0.6 g of guanidine carbonate (origin: Fluka)
in 2.77 g of water. The obtained solution was gradually added to
the reaction mixture obtained in step b). The system was then
maintained at 70.degree. C. for 3 hours under mechanical stirring
of 500 rpm.
[0113] The obtained capsules were then characterized. A mean
particle size of 12 .mu.m was measured by laser diffraction
measurements (MasterSizer, Malvern Instruments Ltd). A zeta
potential of 64.8.+-.0.4 mV was measured with a Zetasizer Nano ZS
(Malvern Instruments). This high value indicates a high density of
the cationic groups at the surface of the microcapsules.
Example 4
Preparation of Microcapsules According to the Invention
[0114] a) An amount of 0.85 g of quaternized triethanolamine
(origin: Fluka) was mixed into a solution with 3.5 g of
Desmodur.RTM. N100 (solvent-free aliphatic polyisocyanate resin
based on hexamethylene diisocyanate, origin: Bayer), 3.0 g of the
perfume described in Table 1 and traces of DABCO (1,4-diazabicyclo
[2.2.2]octane, origin: Fluka). This mixture was dispersed using an
Ultra Turax at 24000 rpm for 1 minute and the resulting solution
was kept at room temperature under magnetic stirring for 15
minutes.
[0115] b) The reaction mixture was then dispersed in 12 g of the
perfume described in Table 1 using an Ultra Turax at 24000 rpm for
1 minute.
[0116] c) We added slowly 27 g of water into the mixture and we
dispersed it using an Ultra Turax at 24000 rpm for 5 minutes.
[0117] d) An aqueous solution of guanidine carbonate was then
prepared by dissolving 1.0 g of guanidine carbonate (origin: Fluka)
in 3.0 g of water. The obtained solution was gradually added to the
reaction mixture obtained in step c). The system was then
maintained at 70.degree. C. for 16 hours under mechanical stirring
of 500 rpm.
Example 5
Preparation of Microcapsules According to the Invention
[0118] a) An amount of 0.43 g of 2-aminoethyl-trimethylammonium
chloride hydrochloride (origin: Fluka) was dissolved in 0.25 g of
water then the pH was adjusted to about 11 by using a 30% sodium
hydroxide solution. The resulting solution was mixed with 1.79 g of
Desmodur.RTM. N100 (solvent-free aliphatic polyisocyanate resin
based on hexamethylene diisocyanate, origin: Bayer). The entire
mixture was maintained under magnetic stirring at room temperature
for 7 minutes.
[0119] b) The reaction mixture was then dispersed in 7.56 g of the
perfume described in Table 1 using an Ultra Turrax at 24000 rpm for
1 minute. An amount of water of 13.18 g was then added in this
dispersion, which was then mixed using an Ultra Turrax at 24000 rpm
for 5 minutes.
[0120] c) An aqueous solution of guanidine carbonate was then
prepared by dissolving 0.68 g of guanidine carbonate (origin:
Fluka) in 1.66 g of water. The obtained solution was gradually
added to the reaction mixture obtained in step b). The system was
then maintained at 70.degree. C. for 4 hours under mechanical
stirring at 600 rpm.
[0121] The obtained capsules were then characterized. A mean
particle size of 7 .mu.m was measured by laser diffraction
measurements (MasterSizer, Malvern Instruments Ltd). A zeta
potential of 46.3.+-.0.2 mV was measured with a Zetasizer Nano ZS
(Malvern Instruments). This high value indicates a high density of
the cationic groups at the surface of the microcapsules.
Example 6
Determination of the Capsules Structure
[0122] The structure of the capsules was determined by confocal
laser scanning microscopy (CLSM). This technique allowed the
observation of microcapsules and the analysis of the composition of
the internal phase, due to the addition of traces of Nile Red to
the perfume and of fluorescin to the water at the beginning of the
above described process. FIG. 2 represents the CLSM image of the
capsules of Example 3. The perfume phase is represented in light
grey, due to the fluorescence of the Nile Red, the inner aqueous
phase is represented in dark grey due to the fluorescence of
fluorescin, and the external aqueous phase is represented in black
(no fluorescence). The multicore structure of the capsules is
evident, since in several capsules, an inner aqueous phase (in dark
grey) is surrounded by an inner perfume (oily) phase (in light
grey).
[0123] FIG. 3 is another representation of the capsules of Example
3, obtained by the CLSM method but without using fluorescence. FIG.
3a) represents the CLSM image of the microcapsules of Example 1,
while FIG. 3b) represents the microcapsules of Example 2. Again,
these figures show that most of the capsules formed have a
multicore structure.
Example 7
Liquid Detergent Comprising the Microcapsules of the Invention and
Stability of the Microcapsules
[0124] The microcapsules of Example 1 were mixed at 0.75% into the
commercially available unperfumed Tide.RTM. 2.times.HE Free of
perfume & dye (trademark of Procter and Gamble, USA)
concentrated liquid detergent. These products were then stored at
38.degree. C. for three weeks.
[0125] The free perfume was analysed every week. The results are
shown in FIG. 4. After three weeks of storage, the amount of free
perfume for each ingredient did not exceed 20%, except for hexyl
salicylate. These percentages were only slightly higher than those
determined after one and two weeks. This indicates a good stability
of the perfume retention in the microcapsules in liquid
detergent.
Example 8
Fabric Softener Comprising the Microcapsules of the Invention and
Stability of the Microcapsules
[0126] A fabric softener base was prepared by admixing the
following ingredients, in the amounts indicated.
TABLE-US-00002 TABLE 2 Formulation of the concentrated fabric
softener base Ingredient % Stepantex VL90 A Diester Quat.sup.1)
16.50 Proxel GXL.sup.2) 0.04 CaCl.sub.2 (10% aqueous solution) 0.20
Water 83.26 .sup.1)Origin: Stepan .sup.2)Origin: Avecia
[0127] The microcapsules suspension of Example 1 was mixed at 1.25%
into the unperfumed softener base prepared above. These products
were then stored at 38.degree. C. for three weeks.
[0128] The free perfume was analysed every week. The results are
shown in FIG. 5. After three weeks of storage, the amount of free
perfume only slightly exceeded 20%, except for hexyl salicylate.
These percentages were only slightly higher than those determined
after one and two weeks. This indicates a good stability of the
perfume retention in the microcapsules in the fabric softener
base.
[0129] The rate of perfume partitioning between the microcapsules
and the fabric softener base is comparable to the one observed in
the liquid detergent (see Example 7).
* * * * *